Without further details, it's almost impossible to provide anything useful here.
However, I think the relevant topic is reentrant VIs, or reentrancy in LabVIEW. I would suggest reading the "Simultaneously Calling SubVIs from Multiple Places" section of Application Note 114 in the DevZone: http://zone.ni.com/devzone/conceptd.nsf/webmain/D2E196C7416F373A862568690074C759?opendocument Regards, John Lum National Instruments
